Efeito de diferentes protocolos de envelhecimento e do sistema de fresagem na rugosidade superficial de uma cerâmica de zircônia

Abstract

The zirconia has found wide application in dentistry due to its high mechanical strength and excellent aesthetic properties. However, the surface degradation suffered in hydrothermal environment is of great concern. Purpose: To evaluate the influence of milling and aging protocols on the surface roughness of ceramic zirconia system. Methods: A standard metal cast was made to prepared standardized zirconia crowns systems (N=40). The copings were divided into 8 groups (n=5), in accordance with the factors "aging" and "milling system" (CAD / CAM-Neodent and MAD / MAM Zirkonzahn) ": CADct and MADct (control groups); CADaut and MADaut (autoclave); CADph and MADph: pH cycling during eight days and CADtc and MADtc: thermal cycles between 5° and 55°C (12,000 cycles). After treatments, the surface roughness (Ra) was obtained through a digital optical profiler and analysis of x-ray diffraction was performed on two samples of each group (n=16). The data (nm) obtained were statistically analyzed by 2- Ways ANOVA. Results: aging protocols (p=0.5255) and milling systems (p=0.1126) did not influence the surface roughness of ceramic zirconia. Mean roughness (nm) for the experimental groups (CADct, MADct, CADaut, MADaut, CADph, MADph, CADtc and MADtc) were as follows: 1.0620A, 1.0780A, 1.0280A, 0.8060A, 0.8460A, 1.0340A, 1.020A, 1,0220A. Conclusion: The aging methods that simulate the oral environment and milling systems did not influenced the values of surface roughness.